Brachial plexus cords: a morphological study.

BACKGROUND AND OBJECTIVES The brachial plexus represents an important network of nerves, commonly approached in nerve blocks prior to surgical procedures. Therefore, the knowledge of its anatomy is indispensable so those procedures can be carried out accordingly. The objective of the present study was to analyze the morphology of brachial plexus cords with special emphasis to its topographic relationships. METHODS This study was undertaken by dissecting the cervical, axillary, and brachial regions of a human cadaver fixed in 10% phormol, from the Human Anatomy Laboratory of the Morphology Department of Universidade Federal de Santa Maria. Access to the cords was obtained by pushing back the pectoralis minor and pectoralis major muscles, clavicular section, and extraction of part of the subclavius muscle. RESULTS Cords originated from the anterior and posterior divisions of the trunks (upper, middle, and lower) of the brachial plexus. The lateral fascicle originated from the anterior divisions of the upper and middle trunks; the posterior, from the posterior divisions of the trunks; and the middle fascicle consisted from the continuation of the anterior division of the lower trunk. The cords showed relationships with the axillary artery, and they were located posteriorly to the pectoralis minor muscle, close to its insertion on the coracoid process. CONCLUSIONS The results were in concordance with the anatomical descriptions of classical authors. This study allowed the analysis of the morphology of the brachial plexus cords, demonstrating its main topographic relationships.